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2 Sheets-Sheet 1. J. 'R. TREGO. PHOTOGRAPHIG SHUTTER. No. 422,664.Patented Mar. 4, 1890.

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(No Model.) 2 Sheets-Sheet 2.

J. R. TREGO. PHOTOGRAPHIG SHUTTER.

No. 422,664 Patented Mar. 4, 1890.

n. PETERS, Mmrw-r. wuum' old UNITED STATES PATENT OFFICE.

JOSEPH R. TREGO, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR OF ONE HALF TOHENRY O. OWENS, OF SAME PLACE.

PHOTOGRAPHIC SHUTTER.

SPECIFICATION forming part of LettersPatent No. 422,664, dated March 4,1890.

Application filed September 2, 1889. Serial No. 322,789. (No model.)

To all whom it may concern.-

Be it known that I, J OSEPH R. TREGO, of the city and county of SanFrancisco, State of California, have invented an ImprovementinPhotographic Shutters; and I hereby declare the following to be a full,clear, and exact description of the same.

My invention relates to improvements in photographic shutters and themeans for, operating the same.

It consists of an air-impelled pistonreciprocating in a cylinder, apiston-rod and slide, and a lever connected with the shutter and engagedby said slide, so as to be opened, and mechanism for closing. theshutter when released, together With certain details of construction,which will be more fully explained by reference to the accompanyingdrawings, in which Figure 1 is a rear end view of a camera, showing adouble transversely-moving shutter and the mechanism by which it isopened. Fig. 2 is a front end view showing the shutters closed. Fig. 3is a view showing the mechanism for operating a shutter which is hingedfrom below. Fig. 2 is an enlarged sectional view of the attachment ofthe arm G.

A is the front end of the camera, and B B are the leaves of the shutter,which are hinged in the lens-board below the opening through which thepicture is to be taken, these leaves opening from and closing across avertical central line in the usual manner. They are connected togetherby a lever-arm D, so as to open and close simultaneously, and, areactuated as follows: 0 is a pin or shaft extending through thelens-board of the camera and one of the leaves of the shutter, andhaving a le ver-armD upon itsinside connecting the shutters so that theymove together, with a spring E, which acts to close the shutters, thetension of this spring being regulated by means of a suitablethumb-screw F. Upon the opposite or outer end of thepin or shaft 0 is alever arm G. This leverarm is engaged by a slide or arm H, which isfixed to the pistonrod 1, and projects to one side of said rod, so thatone end of this slide travels in a guidingslot J in a plate, upon whichthe air-cylinder K is fixed. At the opposite end of this plate is fixeda guide-post L, through which the pis= ton-rod travels and by which itis kept in line. A piston is suitably fitted within the cylinder, and isimpelled in one direction by the pressure of air introduced through thetube M, the force being produced by the usual compression-bulb which isused for this purpose.

- The operation will then be as'follows: The compressed air beingsuddenly forced into the rear end of the cylinder will force the pistonto the end of its stroke, carrying with it the slide, which is fixed tothe piston-rod. This slide engages the point of the lever-arm G, whichis fixed to the shaft 0, and acting through this shaft it opens theshutters with a rapidity depending on the speed of the piston. As thelever-arm travels in the arc of a circle about the shaft C, it will bemanifest that as soon as the slide has passed beyond the arc of thelever-arm this arm will be released and the shutters will closeinstantly with a speed depending upon the tension of the closing spring.

To hold the shutter open for focussing, the end X of the piston-rod ispushed in flush with the cylinder head. In this position the action ofthe spring upon the lever-arm produces a lateral pressure upon theslide, thus holding the shutter open as long as may be So desired. WVhenthe focus has been obtained,

a pressure upon the bulb will close the shutters, and the plate may beintroduced and the exposure made without further work. For atime-exposure the lever N is turned up in front of the slide H, whichstops said slide in the position described above.

Itwill be manifest that various forms of shutters may be used to suitthe diiferent classes of work to be done, the operation being similar ineach case.

In Fig. 3 I have shown a single shutter hinged below the aperture andoperated in the same manner by a piston and slide, and a lever armengaged by the slide, but mov ing at right angles to the one describedin Figs. 1 and 2. In this case the shutteris not connected directly withthe shaft C but the lever upon theinner end of this shaft engages asecond crank-arm, which is connected with roe or formed in the shaftupon which the shutter is journalcd. The spring in this case is alsoconnected with the crank arm of the journalshaft and acts to close theshutter when re leased, as before described. The shutter may be stoppedwhen opened by a lever similar to that shown in Figs. 1 and 2, theoperation being in all respects similar, and the only changes made beingsuch mechanical changes as are necessary to ada-ptit to the particularform of shutter used.

The arm G is pivoted within the head of the shaft 0, so as to have aclearance, as shown in Fig. 2, to allow the slide II to pass the arm onits return, and a spring 9 returns the arm to its place in the head, inposition to engage the slide again. This permits one to repeat theexposure.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-- 1. In combination with a photographicshutter, the cylinder, the piston moving therein, the piston-rod and theslide or arm carried by said rod, and a shaft adapted to open theshutter and having a projecting arm or crank which is engaged by the armor slide upon the projecting rod and is adapted to travel in an arc of acircle about the shaft, whereby the movement of the piston and rod actsto open the shutter, substantially as described.

2. The photographic shutter having the shaft connected therewith andadapted to open the shutter when rotated, an arm extending radially fromsaid shaft, a cylinder with a reciprocating piston and piston-rod, and

an arm or slide upon the piston-rod adapted to engage the lever-arm fromthe shutter-actuating shaft and release said lever-arm after the slidehas passed beyond the arc of the lever-arm, substantially as described.

3. A photographic shutter having a rotary shaft connected with it,whereby it may be opened, and a spring whereby it may be closed whenreleased, an arm projecting from the r0- tary shaft, and a slide or armconnected with the piston or piston-rod of an air-cylinder, said slideengaging the arm upon the shutteractuating shaft, so as to open theshutter when the piston is impelled to the front end of the cylinder andto release the shutter before the piston has completed its stroke,substantially as described.

at. In combination with a photographic shutter, the shutter-actuatingmechanism, as described, and the stop or lever adapted to stop the slidebefore it passes the lever-arm, substantially as described.

5. In a camera-shutter, the lever-arm G, pivoted so as to swing in ahead fixed upon the shaft 0, and the returning-spring g, substantiallyas described.

In witness whereof I have hereunto set my hand.

JOSEPH R. TREGO.

Witnesses:

S. H. NoUnsE, II. 0. LEE.

